Severity categories hazard analysis

Ref. 39 suggests an initial qualitative hazards analysis early in systems design, with only general levels of hazard probabilities identified, in addition to severity categories. An example of such a qualitative ranking from Ref. 39 appears in Table V. 

The hazard identification and analysis processes shown in SEMI SI0-1103 duplicate those in SEMI S2-0706. In the risk assessment process, the severity of outcome and likelihood of occurrence are to be identified and categorized. In Appendices, recommended categories for likelihood and severity are given, as well as matrices showing risk categories. The exhibits are comparable to those shown in Chapter 8, A Primer on Hazard Analysis and Risk Assessment. ... 

Again, a PHL is developed (use Appendix C as a starting point). The PHL is divided into hazard categories. The functional tree is created. Then the actual facility hazard analysis is started. Each hazard is assigned a severity and probability level, and the other portions of the hazard analysis worksheet are completed. Then a system safety assessment is performed and the worksheet results are analyzed. 

ABSTRACT Retention levels of road safety barriers are specified on the basis of risk assessment taking into account accidental data and further information available in the Czech Republic and also selected recommendations of Road Safety Association PIARC. The method of Bayesian networks is applied in the analysis and compared with event tree method. Newly proposed classes of retention for several categories of road surroundings considering the intensity of heavy traffic and two levels of hazard situation are incorporated to the revision of national prescriptive document that is expected to enhance the road safety. 

NUCLEAR HAZARD CATEGORY 2 FACILITIES. This category requires use of one of several analytical methods for developing qualitative accident scenarios. The choices are generally compatible with the requirements of the PSM Rule. If the PSM Rule requirements for PrHAs are met, the resulting analysis should significantly contribute to the analysis required under the DOE-STD-1027-92 for release mechanisms. However, analyses beyond PSM Rule requirements may be needed to comply with other SAR requirements for Nuclear Hazard Category 2 Facilities. 

Once the hazards were identified, the severity of each hazard was evaluated by considering the worst-case loss associated with the hazard. In the example, the losses are evaluated for each of three categories humans (H), mission (M), and equipment (E). Initially, potential damage to the Earth and planet surface environment was included in the hazard log. In the end, the environment component was left out of the analysis because project managers decided to replace the analysis with mandatory compliance with NASA s planetary protection standards. A risk analysis can be replaced by a customer policy on how the hazards are to be treated. A more complete example, however, for a different system would normally include environmental hazards. 

Risk assessment is a process that commences with hazard identification and analysis that produces an estimate of the severity of harm or damage that may result if an incident or exposure occurs, followed by an estimate of the probability of an incident or exposure occurring and concluding with a risk category (e.g.. Low, Moderate, Serious, High). 

I Applicable violation means the same as relevant violation in respect to scoring Behavior Analysis Safety Improvement Categories (BASICs) in the Safety Measurement System (SMS). Applicable violation includes any violation of the Federal Motor Carrier Safety Regulations (FMCSRs) or hazardous materials regulations (HMR) appearing in the severity weighting tables for a specific BASIC I during a relevant inspection. 

System safety typically applies the qualitative risk characterization method because for a large system with many hazards, it can become cost-prohibitive to quantitatively model, analyze, and predict the risk of each and every hazard. In addition, low risk hazards do not require the refinement provided by quantitative analysis. It may be necessary to conduct a quantitative analysis only on a select few high consequence hazards. Experience over the years has proven that qualitative methods are very effective, and in most cases provide decision-making capability comparable to quantitative analysis. Qualitative risk characterization provides a very practical and effective approach when cost and time are concerns, and/or when there is very little supporting data available. The key to developing a qualitative risk characterization approach is by carefully defining severity and mishap probability categories. 

---